1. Field of the Invention
The present invention relates to a method and device for polishing a thin-plate metal ring for use in an endless belt of a continuously variable transmission.
2. Description of the Related Art
For example, a plurality of elements stacked/arranged in an annular form and bound by a laminated ring constituted by stacking a plurality of metal rings have been used in a belt for power transmission for use in a continuously variable transmission. The metal ring constituting this type of laminated ring is formed in an endless band shape by slicing a cylindrical metal drum every predetermined width by a thin disc shaped grinding stone. Moreover, since burrs are generated in a side edge of the metal ring cut from the cylindrical drum, it is necessary o polish the burrs. Even when a few burrs are generated in the side edge of the metal ring, it is necessary to polish the side edge of the metal ring and to finish the side edge in a high-precision curved shape.
As a conventional method of polishing the side edge of the metal ring, a method described, for example, in Japanese Patent Laid-Open No. 2001-241512 is known. This polishing method of the metal ring is called barrel polishing, the metal rings which are works are mixed in a barrel filled with the grinding stones called media, and the barrel is rotated together with the metal rings and media. When the metal rings are stirred together with the media in the barrel in this manner, the media are brought into contact with the side edges of the metal rings to polish the side edges of the metal rings.
However, when the barrel polishing is performed, more media abut on an outer peripheral surface side rather than the inner side of the metal ring, and this causes a disadvantage that the polishing of inner and outer corners of the side edge of the metal ring becomes nonuniform. When the metal rings are projected into the barrel, and at the time of the barrel polishing, there is a possibility that the metal rings collide with one another and are scratched. These metal rings are removed by inspection, but have been causes for deterioration of yield.
On the other hand, in Japanese Patent Laid-Open No. 2002-248522, a method of polishing the side edge of the metal ring by the grinding stone is disclosed. However, for the polishing by the grinding stone, since a shape of the side edge of the metal ring is influenced by that of the grinding stone, it is frequently necessary to change the grinding stone, and there is a disadvantage that operation efficiency drops.
To solve the disadvantages, an object of the present invention is to provide a method and device for polishing a metal ring, in which a side edge of the metal ring can be polished without performing barrel polishing or polishing by a grinding stone to solve the above-described disadvantages.